Duration of Pupillary Unresponsiveness to Light: A Physiological Adjunct to Electroencephalography and Motor Seizure Duration Monitoring During Electroconvulsive Therapy.

BACKGROUND: During electroconvulsive therapy (ECT) sessions, we observed that the time taken for the return of pupillary response to light (ROPL) outlasted both the electroencephalography (EEG) and the motor seizure duration after the delivery of the electrical stimulus to produce convulsions. OBJECTIVE: The objective of this study was to investigate whether ROPL can be used as a marker of cessation of seizure activity in the brain after ECT and also to study the effect of atropine premedication on seizure activity during ECT. METHODS: Forty-one patients underwent 82 sessions of ECT in a cross-over design study. The duration of motor seizure, EEG seizure, and time for ROPL was observed and compared. RESULTS: The ROPL consistently outlasted EEG and motor seizures; the difference in their mean durations was statistically significant P < 0.05. There was good correlation among the 3 parameters. Atropine premedication did not alter the seizure activity and ROPL after ECT. CONCLUSIONS: The ROPL after ECT stimulus is a good bedside monitor for termination of seizure activity and can be a valuable adjunct to surface EEG in monitoring the duration of epileptic activity after delivery of ECT.

Acute kidney injury in survivors of surgery for severe traumatic brain injury: Incidence, risk factors, and outcome from a tertiary neuroscience center in India.

BACKGROUND: Non-neurological complications like acute kidney injury (AKI) can affect outcome of traumatic brain injury (TBI). This study aims to analyze the incidence, predictive factors, and impact of AKI in operated patients with severe TBI. METHODS: We retrospectively reviewed the data of 395 patients who underwent surgery for severe TBI and survived to be discharged from the hospital over a 1-year period. Of these, 95 patients were finally included in the analysis. Their demographic data, laboratory parameters, and clinical courses were reviewed. Diagnosis and staging of AKI was made using Acute Kidney Injury Network (AKIN) criteria. RESULTS: The incidence of AKI was 11.6% (11 patients). Out of the 11 patients who had AKI, 7 were in stage I (63.6%), 3 were in stage II (27.3%), and 1 in stage III (9.1%). Nine Patients (81.8%) developed AKI within 5 days of admission. Aminoglycoside therapy had an association with occurrence of AKI. There was no mortality and none of the patients required renal replacement therapy (RRT). Renal function of all these patients returned to baseline before hospital discharge. Hospital stay and intensive care unit (ICU) stay were longer and Glasgow coma scale (GCS) was lower in patients with AKI when compared with patients without AKI group at discharge. CONCLUSION: Reversible AKI without need for RRT occurred in nearly 12% of patients with severe TBI requiring surgical intervention. Aminoglycoside therapy was the only predictive factor for the occurrence of AKI. Patients with AKI have a longer period of mechanical ventilation, longer ICU and hospital stay, and poorer GCS at discharge.

Fall in inspired oxygen and anaesthetic agent concentrations during change of soda lime absorber.

Following an episode of reduction in inspired oxygen concentration (FiO(2)) and inhalational agent concentration (Fi agent) during the changing of a soda lime absorber, We conducted an in vitro experiment to understand the impact of disconnection of the absorber on inspired gas dilution at different fresh gas flows. We found that both in Dräger Fabius GS and Primus anaesthesia work stations, disconnection of the absorber caused progressive reduction in FiO(2) and Fi agent as the FGF was decreased. The operating principle of fresh gas decoupling (FGD) valve is a potential source of this complication, which must be kept in mind while changing the soda lime during the course of surgery where an anaesthetic work stations utilizing FGD valves are used.

Anesthetic management of patients with Joubert syndrome: a retrospective analysis of a single-institutional case series.

OBJECTIVE: To analyze the anesthetic techniques used for sedation during magnetic resonance imaging (MRI) study of patients with Joubert syndrome (JS) and assess the safety and efficacy of these anesthetic regimens in these children. BACKGROUND: Joubert syndrome is a rare neurological disorder with significant anesthetic implications. This study describes the anesthetic management of children with JS undergoing MRI study with different anesthetic agents and implications of various anesthetic techniques in these patients. MATERIALS AND METHODS: The records of ten patients with JS undergoing MRI study with different anesthetic techniques were retrospectively reviewed over the last 5 years. RESULTS: The patients were aged between 6 months and 21 years. The most commonly used sedation technique involved use of alpha-2 agonists, and this technique had least complications such as apnea and patient movement during imaging. None of the patients had postanesthetic respiratory problems, although one patient receiving propofol had apnea and desaturation on induction requiring airway intervention. CONCLUSION: Alpha-2 agonist based anesthetic technique appears to be most suitable for sedation during MRI study in patients with JS with respect to adverse events and outcome.

Seasonal variation in the clinical recovery of patients with Guillain Barré syndrome requiring mechanical ventilation.

BACKGROUND: Guillain Barré Syndrome (GBS) has a variable clinical course. The influence of season on the rate of recovery has not been evaluated previously, despite documentation of seasonal variation in the occurrence of GBS. This study evaluated the influence of season on the rate of recovery from GBS. MATERIALS AND METHODS: Records of 184 patients with GBS over a 10-year period were reviewed. Patients were divided into four groups depending on the date of admission: Q1 (March-May), Q2 (June-August), Q3 (September-November), and Q4 (December-February). Demographic characteristics and recovery characteristics (duration of mechanical ventilation, ICU and hospital stay, and time for recovery from the time of initiation of definitive therapy) were compared across the four quarters. RESULTS: There was no significant difference in age, antecedent illnesses, treatment received, electrophysiological findings, and muscle power at admission across the four groups. Significant differences among various seasons were found with respect to duration of mechanical ventilation (23 ± 20, 36 ± 34, 27 ± 22, and 38 ± 28 days for Q1-Q4, respectively; P = 0.05), ICU stay (27 ± 22, 40 ± 37, 31 ± 23, and 43 ± 30 days for Q1-Q4, respectively; P = 0.05), hospital stay (42 ± 28, 55 ± 44, 47 ± 34, and 72 ± 54 days for Q1-Q4, respectively; P = 0.02), and time for recovery from treatment (15 ± 14, 29 ± 34, 18 ± 14, and 29 ± 20 days for Q1-Q4, respectively; P = 0.02). CONCLUSIONS: This study demonstrates a seasonal variation in the recovery of patients with GBS requiring mechanical ventilation. Patients admitted in Q1 have the fastest recovery and those in Q4 have the slowest recovery.

Opioid versus Nonopioid Analgesia for Craniotomy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Despite the use of intraoperative opioid analgesia, postoperative pain is often reported by patients undergoing craniotomies. Opioids also cause undesirable side effects in neurosurgical patients. Hence, the role of nonopioid analgesia has been explored for craniotomies in recent years. METHODS: This systematic review evaluated evidence from randomized controlled trials (RCTs) comparing opioid and nonopioid analgesia during craniotomies regarding postoperative pain, recovery, and adverse events. RESULTS: Of the 10,459 records obtained by searching MEDLINE, Embase, and Web of Science databases, 6 RCTs were included. No difference was observed in pain scores between opioid and nonopioid analgesia at 1 and 24 hours after surgery: mean difference (MD), 1.11 units; 95% confidence interval [CI], -0.16 to 2.38, P = 0.09 and MD, -0.06 units; 95% CI, -1.14 to 1.01, P = 0.91, respectively. The time for first postoperative analgesic requirement was shorter with opioids but was not statistically significant (MD, -84.77 minutes; 95% CI, -254.65 to 85.11; P = 0.33). Postoperative nausea and vomiting (relative risk = 1.60; 95% CI, 0.96-2.66; P = 0.07) was similar but shivering (relative risk = 2.01; 95% CI, 1.09-3.71; P = 0.03) was greater in the opioid group than nonopioid group. CONCLUSIONS: There were no important differences in clinical outcomes between the groups in our review. The GRADE certainty of evidence was rated low for most outcomes. Available evidence does not suggest superiority of intraoperative nonopioid over opioid analgesia for postoperative pain in patients undergoing craniotomy. More studies are needed to firmly establish the role of nonopioid intraoperative analgesics as an alternative to opioids in this population.

Prognostic Value of Tissue Oxygen Monitoring and Regional Cerebral Oxygen Saturation Monitoring and Their Correlation in Neurological Patients with Sepsis: A Preliminary, Prospective, Observational Study.

BACKGROUND: There is paucity of literature on the prognostic value of tissue oxygen saturation (StO2) and regional cerebral oxygen saturation (rSO2) in neurological patients with sepsis. In this preliminary study, we investigated the prognostic value of StO2 and rSO2 in a group of neurological patients and correlated StO2 and rSO2 with hemodynamic and metabolic parameters. MATERIALS AND METHODS: This preliminary, prospective observational study was conducted in 45 adult neurological patients admitted to intensive care unit. Once a diagnosis of sepsis or septic shock was established, parameters of oxygenation (StO2, rSO2, central venous oxygen saturation [ScvO2]), serum lactate, illness severity scores (Acute Physiology and Chronic Health Evaluation score, Sequential Organ Failure Assessment score, Glasgow Coma Scale) were recorded at 0, 6, 12, 24, 36, and 48 hours, and once daily thereafter. Outcomes were in-hospital mortality attributable to sepsis and the Glasgow outcome score at hospital discharge. RESULTS: There was a moderately positive correlation between StO2 and rSO2 at baseline (r=0.599; P=0.001). StO2, illness severity scores and serum lactate, but not rSO2, were significantly different between survivors (n=29) and nonsurvivors (n=16) at baseline and during the first 48 hours. An rSO2 of 62.5% had a sensitivity of 83% and specificity of 67% to differentiate survivors and nonsurvivors of septic shock at 48 hours. StO2 had a higher correlation with ScvO2 and serum lactate than rSO2. CONCLUSIONS: StO2 prognosticates survival and favorable/unfavorable outcomes in neurological patients with sepsis. The role of rSO2 in predicting survival in milder form of sepsis is doubtful.

Analgesia Nociception Index Monitoring During Supratentorial Craniotomy.

BACKGROUND: Objective monitoring of pain during and after surgery has been elusive. Recently, Analgesia Nociception Index (ANI) monitor based on the high frequency component of heart rate variability has been launched into clinical practice. We monitored analgesia during craniotomy using ANI monitor and compared it with cardiovascular parameters and response entropy (RE) of entropy monitor. MATERIALS AND METHODS: In 21 patients undergoing a craniotomy for a supratentorial lesion, we monitored ANI, heart rate (HR), mean arterial pressure (MAP), state entropy, and RE throughout the surgery. Also, ANI, hemodynamic variables and spectral entropy values were noted at the times of maximal stimulation, such as induction, intubation, head pin fixation, skin incision, craniotomy, durotomy, and skin closure. We also compared ANI with RE during administration of bolus doses of fentanyl. RESULTS: There was an inverse correlation between ANI values and the hemodynamic changes. When the HR and MAP increased, ANI decreased suggesting a good correlation between hemodynamics and ANI values during the times of maximal stimulation. State entropy and RE did not change significantly in response to bolus doses of fentanyl administered during the course of surgery, while ANI increased significantly. CONCLUSION: In neurosurgical patients undergoing elective supratentorial craniotomy, ANI measures response to noxious stimuli with at least as much reliability as hemodynamic variables and changes in ANI parallel the changes in HR and MAP. ANI is superior to RE for measurement of response to noxious stimuli.

Analgesia Nociception Index-guided intraoperative fentanyl consumption and postoperative analgesia in patients receiving scalp block versus incision-site infiltration for craniotomy.

BACKGROUND: Scalp block or local anesthetic infiltration for craniotomy blunts hemodynamic response to noxious stimuli, reduces opioid requirement and decreases postoperative pain. Analgesia Nociception Index (ANI) provides objective information about the magnitude of pain (rated from 0 to 100 with 0 indicating extreme nociception and 100 indicating absence of nociception) and adequacy of intra-operative analgesia. This study compared intra-operative fentanyl consumption guided by ANI and postoperative pain in patients who receive scalp block with those who receive incision-site local anesthetic infiltration for craniotomy. METHODS: Sixty adult patients undergoing elective supra-tentorial tumor surgery were randomly allocated to receive scalp block or incision-site infiltration after induction of anesthesia. Throughout the intra-operative period, patients received fentanyl 0.5 µg/kg/h and ANI was continuously monitored. Fentanyl 1 µg/kg bolus was administered when ANI decreased to <50. Intraoperative fentanyl consumption was compared using unpaired t-test. Correlation between ANI and postoperative numerical rating scale (NRS) pain score was done using Spearman's rho. RESULTS: The fentanyl consumption (µg/kg/h) was less with scalp block when compared to incision-site infiltration (median [interquartile range]; 1.04 [0.92-1.34] vs. 1.34 [1.18-1.59], P=0.001). Postoperative pain scores were similar [median (interquartile range); 1.5 (0-4) vs. 3 (0-4), P=0.840]. No correlation was observed between postoperative NRS Score and ANI (correlation coefficient = 0.072; P=0.617). CONCLUSIONS: ANI-guided analgesic administration during craniotomy demonstrated lower intra-operative fentanyl consumption in patients receiving scalp block as compared to incision-site local anesthetic infiltration. No correlation was seen between postoperative NRS and ANI.

Quantification of burst suppression and bispectral index with 2 different bolus doses of thiopentone sodium.

Metabolic suppression caused by barbiturates is a major mechanism responsible for their cerebral protective potential. Maximal cerebral metabolic suppression is believed to coincide with electroencephalographic burst suppression. However, many neurosurgical procedures associated with cerebral ischemic threat are still performed in the absence of electroencephalogram monitoring, especially in developing nations. The present study was designed to assess the degree of burst suppression with 2 different doses of thiopentone sodium administered on the background of isoflurane anesthesia intraoperatively. Forty-one patients without any intracranial pathology undergoing elective spinal surgery under a general anesthetic consisting of N2O (60%) in O2 (40%) and isoflurane to maintain a bispectral index (BIS) value of 45 were randomized to receive a thiopentone bolus of either 3 or 5 mg/kg. BIS, burst suppression ratio (BSR), systolic blood pressure, and heart rate were recorded before the bolus and every 15 seconds for first 2 minutes and every 30 seconds for another 8 minutes. During the 10-minute study period after the administration of thiopentone bolus, BIS values were significantly lower in the group that received thiopentone 5 mg/kg compared with the group that received thiopentone 3 mg/kg (P<0.02). BSR>25% was seen in 7 out of 21 patients in the 3 mg/kg group and 10 out of 20 patients in the 5 mg/kg group. There was a statistically insignificant prolongation of the duration of burst suppression with thiopentone 5 mg/kg [243 s (range 75 to 435 s)] compared with thiopentone 3 mg/kg [171 s (30 to 465 s)]. The number of patients who had a BSR >50% was higher among patients who received thiopentone 5 mg/kg as compared with those who received a dose of 3 mg/kg [9/20 vs. 3/21(P<0.02)]. We conclude that thiopentone in a bolus dose of 3 to 5 mg/kg produces only a short duration of incomplete burst suppression. Also, in this dose range, burst suppression does not occur consistently in all patients. The present data suggest that bolus doses of thiopentone in the range of 3 to 5 mg/kg may have very limited value in providing significant metabolic suppression required for intraoperative cerebral protection during temporary ischemic episodes.

Equi-MAC concentrations of halothane and isoflurane do not produce similar bispectral index values.

Minimum alveolar concentration (MAC) has been traditionally used to measure the potency of an inhalational anesthetic agent. Recently, bispectral index (BIS) derived from the frontal cortical electroencephalogram has been used frequently for quantifying the hypnotic component of anesthesia. The present study was designed to examine the BIS values produced by equi-MAC concentrations of halothane and isoflurane. In 34 patients undergoing spinal surgery, BIS and spectral edge frequency (SEF95) were recorded at 3 different concentrations of halothane and isoflurane--namely 0.5, 0.75, and 1.0 MAC. The measurements were made both during wash-in and wash-out phases of the anesthetic agent. Eighteen patients received halothane and 16 received isoflurane. Heart rate, mean arterial pressure, oxygen saturation, and end tidal carbon dioxide pressure values were not different between the 2 groups at various MAC concentrations of the anesthetic agents. BIS and SEF95 values decreased significantly with increasing concentrations of both the anesthetic agents (P<0.001). At any given MAC concentration of the anesthetic, BIS and SEF(95) values were significantly lower under isoflurane compared with halothane anesthesia both during wash-in and wash-out phases (P<0.001). For a given anesthetic agent, BIS values were comparable at equi-MAC concentrations during wash-in and wash-out phases. In conclusion, BIS values are significantly lower under isoflurane compared with halothane anesthesia at similar MAC concentrations. For a given anesthetic agent and a given MAC concentration, the BIS values are similar during wash-in and wash-out phases of anesthesia.

Fentanyl co-administration decreases the induction dose requirement of propofol in patients with supratentorial tumors and not in patients with spinal lesions.

BACKGROUND: The requirement of anesthetic drugs in a patient with an intracranial space-occupying lesion is of relevance to the neuroanesthetist. The requirement is often presumed to have reduced or at least altered. However, not much research has focused on this issue. Hence, we conducted this study to examine whether intracranial tumors reduce the induction dose of propofol in patients undergoing craniotomy based on plasma and effect site concentrations (Ce) of propofol and the effect of additional fentanyl. METHODS: A total of 80 patients were recruited into the study. The study group included patients with supratentorial tumors undergoing craniotomy, and the control group consisted of patients undergoing spinal surgeries. Patients in each group were randomized further to receive propofol alone or propofol preceded by fentanyl for induction of anesthesia. They were divided into the following groups: patients with supratentorial tumor receiving only propofol (group T1), or fentanyl and propofol (group T2); patients who were undergoing spinal surgery and receiving only propofol (group S1) or fentanyl and propofol (group S2). Anesthesia was induced with infusion of propofol through a Target Controlled Infusion pump. At the point of loss of verbal contact, plasma concentration (Cp) and Ce of propofol, time taken for loss of consciousness, and the total dose of propofol required were noted. Hemodynamic variables were recorded before and after induction of anesthesia. RESULTS: There were 19, 21, 19, and 21 patients in groups TI, T2, S1, and S2, respectively. In group T2 the Cp, Ce, time to loss of verbal contact, and dose required for induction were all significantly lower compared with the other groups. There were no significant differences in the study parameters between T1 and S1, whereas the differences were significant between T2 and S2 (Cp: 3.9±1.1 vs. 4.9±1.2 µg/mL; Ce: 2.6±1.0 vs. 3.7±1.2 µg/mL; P<0.05). CONCLUSIONS: Propofol dose for induction of anesthesia was significantly reduced when administered after fentanyl in patients with supratentorial tumors. Tumors per se without fentanyl coadministration do not decrease the propofol requirement for induction of anesthesia.

Predictive model for survival among neurosurgical intensive care patients.

BACKGROUND: Models for prediction of outcome of intensive care patients greatly help the physician to make decisions and are also important for risk stratification in clinical research and quality improvement. At present, there are no major predictive models for neurosurgical intensive care unit (NSICU) patients. This study aimed to develop a predictive model for survival in NSICU patients. METHODS: This is a prospective observational study in the NSICU at a tertiary-care university hospital. The data were collected within 24 hours of admission in all patients admitted to the NSICU. The parameters collected were demographic variables, systolic blood pressure, arterial oxygen tension after resuscitation (PaO2), Glasgow coma score (GCS) and pupillary signs, blood urea, creatinine, albumin, glucose, sodium, potassium, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, alkaline phosphatase, bilirubin, hemoglobin concentration, leukocyte count, platelet count, temperature, and evidence of infection. Mortality or discharge from NSICU was the primary outcome variable. All patients were provided full care until death or discharge from the ICU. Life support was not withdrawn in any of the patient based on the perception of outcome by the treating physician. All variables were compared between survivors and nonsurvivors. Significant variables were analyzed by multivariate logistic regression and a prediction model was developed. RESULTS: Four hundred six patients were included in the study. Three hundred two patients survived and 104 died (mortality of 25.6%). Significant variables on univariate analysis include primary reason for admission, GCS, pupillary reaction, systolic blood pressure, serum albumin, glucose, serum sodium concentration, hypothermia, and infection at the time of admission. Multivariate analysis showed that the significant independent factors for predicting outcome in NSICU patients are age, diagnosis, GCS, pupillary status, albumin, and serum sodium concentration. The predictive model has good discrimination (receiver operating characteristic curve=0.796) and good calibration (P=0.937). The overall accuracy of the model was 81%. CONCLUSIONS: In the current model of prediction of survival in a neurosurgical ICU, age, diagnosis, GCS, pupillary status, serum albumin, and serum sodium are independent predictors of survival in NSICU patients.

Adequate hypnosis at very low isoflurane concentration during craniotomy monitored by electroencephalography.

We report a patient with Parkinson's disease undergoing craniotomy for a brain tumor, who had clinically adequate hypnosis at a very low concentration of isoflurane. While the raw EEG showed low-voltage slow electrical activity, the EEG analyzer of the monitor displayed high burst suppression ratios. The role of intracranial pathology and drug therapy as possible causes of the low anesthetic requirement for adequate hypnosis are discussed. This report also draws attention to the possibility of erroneous analysis of burst suppression by EEG modules.